Field of the Invention
The present invention relates to an aircraft door installed in an airframe surface of an aircraft as well as to an aircraft having the aircraft door.
Description of the Related Art
A wheeled landing gear unit is widely used as landing gear of an aircraft. Some of such landing gear units are designed to be retractable into a landing gear bay installed in an airframe, being deployed outside the airframe from the landing gear bay only before use.
In some cases, such a retractable landing gear unit is equipped with a door which closes an opening of the landing gear bay in order to reduce air resistance while keeping the landing gear unit housed in the landing gear bay (see, for example, Japanese Patent Laid-Open No. 2004-50856).
The door is installed integrally with a leg body of the landing gear unit or installed on the side of the airframe. A base end portion of the landing gear unit is coupled turnably around a shaft installed on the airframe. A door 1 attached to the landing gear unit is designed to close an opening 3a of a landing gear bay 3 on the side of an airframe 2 as shown in FIG. 6A when the landing gear unit is retracted into the landing gear bay by turning around the shaft.
However, because of pressure changes near an outer surface of the airframe 2, a pressure difference occurs between the outer surface of the airframe 2 and the inside of landing gear bay 3 during flight. When the pressure near the outer surface of the airframe 2 is lower than the pressure inside the landing gear bay 3, due to a differential pressure between an outer surface 1a of the door 1 facing an outer side of the airframe 2 and an inner surface 1b of the door 1 facing an inner side of the landing gear bay 3, a force acts in the direction of opening the door 1 outward.
Consequently, as shown in FIG. 6B, if the door 1 opens outwardly of the airframe 2 due to its own elastic deformation or elastic deformation of the landing gear, the gap between an end portion 1f of the door 1 on a forward side of the airframe and the opening 3a increases, allowing air to flow into the landing gear bay 3. As a result, the pressure inside the landing gear bay 3 increases, further increasing the differential pressure between opposite sides of the door 1 and making the above problem conspicuous.
When the end portion 1f of the door 1 on the forward side of the airframe juts out from the airframe 2 in this way, air resistance increases, adversely affecting flight performance.
This problem is not limited to the door 1 of the landing gear unit, and can occur similarly with any door provided on an airframe surface of the aircraft.
The present invention has been accomplished in view of this technical problem and has an object to provide an aircraft door which can reduce deformation of a door outward of an airframe during flight as well as to provide an aircraft having the aircraft door.